If this disease be annoyed by inoculation from the farcy heads of farcied animals into suppurating sores on other animals, it will be very slow in its progress, especially if it attack the other in a region remote from the lymphatic. If in a saddle-gall, it will make sores very difficult to heal. If there is any such thing as checking the disease in its progress, it is in these three cases.
I have observed that when it has been taken in a sore mouth it has followed down the cheek to the sub-maxillary gland, and ended in a clear case of glanders or farcy. There is another form in which this disease can be taken, and which is, of all others, the most treacherous and dangerous, yet never producing death without the agency of other diseases--always carrying with it the germs of infection, and ready to convey it to debilitated subjects and cause their death. The animal will still live himself, and show no sign of disease further than I am about to describe in the position. It is that which is taken in at the nostrils and attacks the sub-maxillary glands, which become enlarged and will remain so. When these become overloaded there will be a discharge at the nose. That being thrown off, it may be some time before any further discharge will be seen from the same source. In some cases, when the discharge is constant, this can be easily distinguished from gleet or ozena, from the healthy and natural appearance of the membranes of the nose, which at first are pale, then become fiery red or purple. In gleet the discharges from the nostrils, as in ozena, are of a very light color. In glanders they are first of a deep yellow, then of a dirty gray--almost slate color.
Mules affected with glanders of this kind, although it may seem hard from their otherwise healthy appearance, should be destroyed. They indeed carry with them the germs of infection and death, without any visible marks in their appearance to warn those who have the care of animals against their danger.
TEETHING.
As mules seldom change hands to any great extent until two or three years old, it is not deemed necessary here to say any thing of their age until they have reached two years, so as to give the inexperienced a wider scope. The mule's mouth undergoes exactly the same changes as the horse's. Between the ages of two and three these changes begin to take place in the mule's mouth. The front incisor teeth, two above and two below, are replaced by the horse for permanent teeth. These teeth are larger than the others, have two grooves in the outer converse surface, and the mark is long, narrow, deep, and black. Not having attained their full growth, they are somewhat lower than the others, the mark in the two next nippers being nearly worn out, and is also wearing away in the corner nippers.
A mule at three years old ought to have the central permanent nippers growing, the other two pairs uniting, six grinders in each jaw, above and below, the first and fifth level with the others, and the sixth protruding. As the permanent nippers wear and continue to grow, a narrow portion of the cone-shaped tooth is exposed to the attrition; and they look as if they had been compressed. This is not so, however; the mark of some gradually disappears as the pit is worn away. At the age of three and a half or four years the next pair of nippers will be changed, and the mouth at that time cannot be mistaken. The central nippers will have nearly attained their full growth, and a vacuity will be left where the second stood; or, they will begin to peep above the gum, and the corner ones will be diminished in breadth and worn down, the mark becoming small and faint. At this period also the second pair of grinders will be shed. At four years the central nippers will be fully developed, the sharp edges somewhat worn off, and the marks shorter, wider, and fainter. The next pair will be up, but they will be small, with the mark deep and extending quite across. Their corner nippers will be larger than the inside ones, yet smaller than they were, and flat, and nearly worn out. The sixth grinder will have risen to a level with the others; and the tushes will begin to appear in the male animal. The female seldom has them, although the germ is always present in the jaw. At four years and a half, or between that and five, the last important change takes place in the mouth of the mule. The corner nippers are shed, and the permanent ones begin to appear. When the central nippers are considerably worn, and the next pair are showing marks of wear, the tush will have protruded, and will generally be a full half inch in height. Externally it has a rounded prominence, with a groove on either side, and is evidently hollow within. At six years old the mark on the central nippers is worn out. There will, however, still be a difference of color in the center of the tooth. The cement filling up the hole made by the dipping in of the enamel, will present a browner hue than the other part of the tooth. It will be surrounded by an edge of enamel, and there will remain a little depression in the center, and also a depression around the case of the enamel. But the deep hole in the center of the enamel, with the blackened surface it presents, and the elevated edge of the enamel, will have disappeared. The mule may now be said to have a perfect mouth, all the teeth being produced and fully grown.
What I have said above must not be taken as a positive guide in all cases, for mules' mouths are frequently torn, twisted, smashed, and knocked into all kinds of shapes by cruel treatment, and the inexperience, to use no harsher term, of those who have charge of them. Indeed, I have known cases of cruelty so severe that it were impossible to tell the age of the animal from his teeth.
At seven years old the mark, in the way in which I have described it, is worn out in the four central nippers, and is also fast wearing away in the corner teeth. I refer now to a natural mouth that has not been subjected to injuries. At eight years old the mark is gone from all the bottom nippers, and may be said to be quite out of the mouth. There is nothing remaining in the bottom nippers by which the age of the mule can be positively ascertained. The tushes are a poor guide at any time in the life of the animal to ascertain his age by; they, more than any other of the teeth, being most exposed to the injuries I have referred to. From this time forward, the changes that take place in the teeth may be of some assistance in forming an opinion; but there are no marks in the teeth by which a year, more or less, can be positively ascertained. You can ascertain almost as much from the general appearance of the animal as from an examination of the mouth. The mule, if he be long-lived, has the same effect in changing his general appearance from youth to old age as is shown on the rest of the animal creation.
DISEASES OF THE TEETH.
There are few if any diseases to which the mule's teeth are subject, after the permanent teeth are developed; but during the time of their changes I have been led to believe that he suffers more inconvenience, or at least as much as any other animal--not so much on account of the suffering that nature inflicts upon him, as through the inexperience and cruelty of those who are generally intrusted with his care. I will here speak first of lampass. The animal's mouth is made sore and sensitive by teething; and this irritation and soreness is increased by the use of improper bits. As if this were not enough, resort is had to that barbarous and inhuman practice of burning out lampass. This I do, and always have protested against. If the gums are swollen from the cutting of teeth, which is about all the cause for their inflamed and enlarged appearance, a light stroke of a lancet or sharp knife over the gums, at a point where the teeth are forcing their way through, and a little regard to the animal's diet, will be all that is necessary. It must not be forgotten, that at this time the animal's mouth is too sore and sensitive to masticate hard food, such as corn. With the development of the teeth, however, the lampass will generally disappear.